Meanwhile make sauce by whisking the cornflour, milk, cheese, pepper and nutmeg in a pan with a balloon whisk until simmering and thickened. Continue cooking and stirring for a couple of minutes. Set aside.
In an oven ware dish, cover base with thin layer of meat sauce, a layer of sliced mixed roots, drizzle with one third of sauce and add a single layer of lasagne, breaking sheets as necessary.
Repeat process then finish with final sauce and grated cheese.
Bake for 45 minutes until bubbling.